Carbon for electric-arc lamps.



E. CAIBD. CBBGN FOR ELBUTBIG ABG LAMPS.

Arruonlon funn um. no, 11111.

1,066,183, Patented July 1, 1913.

Affi/aways UNITED STATES PATENT oEEioE.

HARRY CAIRD, 0E CHICAGO, ILLINOIS, ASSIGNOR To HERMANN M. HI'RSCHBERG, 0F

NEW YORK, N. Y.

CARBON FOR- ELECTRIC-ARC `ILlAlvlIPS.

Application tiled August 29. 1911.

.7'0 all 'whom it may con cern v Be it known that I, Hanni' Calin), a citizen of the United- States, residing in the city of Chicago, county of Cook, and State of' Illinois, have invented a certain new and useful Carbon for Electric-Are Lamps, et which the following?r is a specification.

This invention is a carbon for electric are lamps, and it pertains, more particularly, t0 a. carbon of that kind which is provided with a metal conductor embedded or incased A,in the carbon material, said conductor forming a path of low resistance for the flow ofvcurrent through the carbon pencil. 15,

The invention consists ot' a double coiled wire incased within the carbon material in such manner that cach wire of a double coil will Contact throughout its length with the carbon material, whereby a continuous contact is secured between the wire coils and the. carbon material for the purpose oi' conducting the current through the carbon material.

Other features and advantages of the invention vvill appear from the following.,r detailed description taken the drawings.

In tho accompanying,r drawings, Thave illustrated one practical einbodin'ient ot the invention, but the construction Ashown therein is to be understood as illustrative. only, and not as defining the limits ot' the invention.

Figure l is a longitudinal section. on an enlargtal scale. of a carbon embodying,r the invention. Fijrs and 15 are cross 'sections on the lilies 2v-:5 and lis-i5, respectively, of Fig. 1.

The carbon pencil or rod :'i is composed of any usual or preferred carboimetons inaterial. Said rod or'pencil is provided with a continuous channel orfpassagge (i, the saine extendingr from end to end.otl the pencil or rod. Said channel is, preferably, circular in cross section, and is uniform in diameter throughout the length tlurreot.V Said chanA nclopens through the respective ends of the pencil or rod, and it is positioned,` preferably, at one side of the longitudinal axis of said rod or pencil.

The, salient feature of the invention is a metal conductor in the i'ioiin of a double (toil,

wire.v

Specification of Letters Patent.

.in connection lwith Patented July l 1913.

Serial No. 646,612.

ln a preferred einlimliuient ofthe invenlioii. a single wire ol the required gage, is doubled or lient upon itself to produre a loep T, and the two strands; ot nire ai'e. then twisted so as to result in coils H, t). `'l`lie I cenvolutions ot' said coils cross-.or intersect,

as shown in Fig. l, so that, the lines of contact of one coil with the cai-benl material will be oppcsite to. or across troni. the lines ot contact ot' the ether coil with said carbon liiaterial. The coils are composed ot .spring wire. and they are positioned -within the channel oipassage ti so that .said coils will expand snllicientlv to sec-ure goed frictional contact with the walls ol' said channel or,

passage, whereby .said coils are rretained within the carbon material by trietioual contact therewith.

lin the manufacture ot the carbon, the pencil 3 with the pzissae'e'therein is produced in the usual way, and the doubledA conductor in an untwisted or'uncoiled condition is inserted into the into the channel until it can be engaged b v 3i suitable holdin;i device. The free ends ot the doubled conductor are twisted tightly around each other, preferably by a machine, after which the wire is stretched lengthwise, the. loop-7 being drawn into tlie'rod or peucil' as shown in Fig. 1, and said tree ends are released, thus allowing the coils fw', tl to recoil or untwist. lVhen tension is released froni the wire, the coils springr away from each other and expandwithin the carbon, thereby formingr a metal conduetorrof greater diameter than a single strand of wire. lt will be noted that in the operation of twisting the wires4 together to pro-- channel., tlielooped endcol said conductor being: inserted wires released, the two helices resultingtherefrom are free to expand within the.

rod, thus securing firm Contact witilrsaid rod duetto the aforesaid expansion, the area of such contact being double the area of contact in the case ot' a single coil. Furthermore, by interlacing the eoils and expanding them as described/within the pas-v sage of the rod, the coni'olutions of the coils divei'; e as shown in Figpl, thus iinparting` to the coils the functions ot' wedges. the ellei't of which is to secure increased frictional Contact With the interior surface of the carbon and to render the removal of the carbon from the coils, or vice versa, the removal of the coils from the carbon, more diicult than were a single coil employed. The ends 10, 11 are now bent over the end of thev pencil or rod 5, and said bent ends are secured to the sides of said rod by a suitable band or collar l2, the bent exposed ends of the conductor leuning contacts for engagement 'with the Carnon holder of an are lamp. It. is preferred to secure the bent ends l0, ll. at opposite points on the exterior of the pencil or rod 5, as shown, thereby providing two exposed contacts. This is advantageous for the reason that should only one contact be used, and should that hecome broken, it is necessary to withdraw the conductor from the rod or pencil suiliciently to form a. new contact, whereas if two contacts are employed, and shouldL one he broken off, the remaining contact will perform its function Without atl'ecting the position of the conductor Within the chan neled rod.

Having thus' fully described the invention, what I claim as new, and desire to secure by Letters Patent is:

1. An :irc-lamp carbon embodying a rrd composed of carbonaceous material and provided with a longitudinal passage, and a conductor positioned within said passage, said oonduetor consisting of a plurality of coils which are expanded Within the passage and have forcible Contact With the walls thereof, the convolutions of said coils interlacing and crossing each other and said convolutions diverging toward the area of contact with the earbonaeeous material.

2. In an are lamp carbon, a rod composed of carhonaceous material'and provided with a longitudinal channel, a metal conductor positioned within said channel, said conductor comprising a Wire of spring metal doubled upon itself and coiled to form a plurality of helices which are in substantially continuous contact With the carbon material of said rod, the ends of said coils being' bent intro engagement with the outer surface of said rod, and means for securing said hentends of the coils in Contact with the exterior surface of the rod.

ln testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HARRY CAIRD.

Vv'itnesses:

H, T. BERNHARD, J. F. lVioTnicRsnnAo. 

